1
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The area of the region, enclosed by the circle x2 + y2 = 2 which is not common to the region bounded by the parabola y2 = x and the straight line y = x, is:
A
$${1 \over 6}\left( {24\pi - 1} \right)$$
B
$${1 \over 3}\left( {12\pi - 1} \right)$$
C
$${1 \over 3}\left( {6\pi - 1} \right)$$
D
$${1 \over 6}\left( {12\pi - 1} \right)$$
2
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1.6 $$ \times $$ 10-16 s. The frequency of revolution of the electron in its first excited state (in s-1) is :
A
5.6 $$ \times $$ 1012
B
1.6 $$ \times $$ 1014
C
7.8 $$ \times $$ 1014
D
6.2 $$ \times $$ 1015
3
JEE Main 2020 (Online) 7th January Morning Slot
Numerical
+4
-0
Change Language
A beam of electromagnetic radiation of intensity 6.4 × 10–5 W/cm2 is comprised of wavelength, $$\lambda $$ = 310 nm. It falls normally on a metal (work function $$\phi $$ = 2eV) of surface area of 1 cm2. If one in 103 photons ejects an elctron, total number of electrons ejected in 1 s is 10x. (hc = 1240 eVnm, 1eV = 1.6 × 10–19 J), then x is _____.
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4
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A litre of dry air at STP expands adiabatically to a volume of 3 litres. If $$\gamma $$ = 1.40, the work done by air is : (31.4 = 4.6555) [Take air to be an ideal gas]
A
60.7 J
B
100.8 J
C
90.5 J
D
48 J
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